brew install --powerline --vim-powerline ricty

gistfile1.txt

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==> fontforge -lang=py -script /private/tmp/ricty-JOuT/Ricty-3.2.3/scripts/powerline-fontpatcher [] Ricty-Bold.tt
 Executable based on sources from 14:57 GMT 31-Jul-2012-D.
 Library based on sources from 14:57 GMT 31-Jul-2012.
usage: powerline-fontpatcher [-h] [--no-rename] [--source-font font]
                             font [font ...]
powerline-fontpatcher: error: argument font: can't open '[]': [Errno 2] No such file or directory: '[]'

READ THIS: https://github.com/Homebrew/homebrew/wiki/troubleshooting
If reporting this issue please do so at (not Homebrew/homebrew):
  https://github.com/sanemat/homebrew-font/issues